1. Field of the Invention
The present invention relates to a display device, in particular to a display device formed of a thin film semiconductor element.
2. Description of the Related Art
A thin display device which is called an FPD (Flat Panel Display) is becoming more widely used as a display for a portable electronic apparatus such as a mobile device. In particular, a display using an electroluminescent element which emits light when a current flows into a layer including an organic material is promoted for practical use since it has many advantages such as a self-light emission, low power consumption, and fast response.
A display of electronic apparatus which is designed for portable use is required to have various characteristics such as low power consumption, lightweight, thinness, compactness, and a narrow frame. To realize a narrow frame means to increase a ratio occupied by a display portion in the whole display area. With a narrow frame, a display can be more compact without changing the area of a display portion and an area of display portion can be increased without changing the size of the display.
With a narrow frame as described above, a mobile device which is easier to carry, more elegant and stylish can be fabricated without changing the area of a display portion. Moreover, provided that the areas of the display and the display portion are not changed in the design that realized a narrow frame, circuits having various functions can be provided in the frame portion that is left, thus a product with higher additional value can be provided. Accordingly, a preferable product which meets users' demands can be provided. In view of the aforementioned reasons, a development for realizing a narrower frame of display is carried out from various perspectives. (see Patent Document 1)
[Patent Document 1]
Japanese Patent Laid-Open No. Hei 11-288001